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DWI Urine Test

To obtain a conviction for DWI, law enforcement and prosecutors heavily rely on scientific evidence. This evidence usually stems from chemical testing conducted by law enforcement officers at the stop or at another location. Police will test your blood alcohol concentration using a breath, blood or urine sample at the stop, state lab, or hospital. While most think of breathalyzer tests when it comes to DWI, it’s very common for police officers to ask drivers to submit a urine sample if they cannot obtain a BAC reading on a breathalyzer.

Urine analysis is considered to be much more reliable than traditional breath testing for DWI. Law enforcement frequently turn to urine testing if they cannot get an accurate BAC reading or if they suspect the driver is under the influence of drugs. The reason for this is that urine tests are much more accurate at detecting drug use than breathalyzers. Despite these facts, urine testing is not a flawless process. Both human error and issues with the test itself could yield false or skewed BAC results.

If you’ve undergone urine or any type of chemical testing and was charged with DWI, it’s highly recommended you seek legal counsel as soon as possible.

DWI Drug Test Attorney in Houston, Texas

Urine testing is a valuable tool by law enforcement and can be used against you in a DWI case. Plus, the information obtained from said testing isn’t always accurate. For this and many other reasons, we highly encourage you to hire an experienced and skilled criminal defense attorney if you’ve been charged with DWI by a chemical test. All types of DWI testing, whether it’s from a blood, urine, or breath sample, are susceptible to testing and human errors.

If you’re in need of legal counsel, call Horak Law. Matthew Horak of Horak Law has over a decade’s worth of experience he can utilize for your case. He’s worked extensively with DWI cases in the past and assisted hundreds of people who were wrongfully accused of drinking and driving. Plus, his past experience at the Harris County District Attorney’s Office gives him a unique insight into what the prosecutor may be thinking.

To set up your first consultation with Horak Law, call our firm at (713) 225-8000. Horak Law has locations in both The Woodlands and Houston, but we accept clients in other counties including Harris County, Waller county, Brazoria County, Fort Bend County, Galveston County, Montgomery County, and Liberty County.

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Can Alcohol Level Be Tested in Urine?

Driving while intoxicated (DWI) is illegal in Texas and law enforcement use blood-alcohol concentration (BAC) testing to determine a person’s impairment level. These chemical tests calculate a person’s blood-alcohol concentration by measuring the amount of ethanol in a breath, blood, or urine sample. Usually, law enforcement will refer to a breathalyzer test when they suspect a person is under the influence.

However, they may use urine testing if they think the driver is under the influence of a controlled substance. The reason for this is urine testing is much more accurate at detecting drugs and their terpenes. Law enforcement do still use urine analysis when determining a person’s impairment level though. The test measures the number of grams of alcohol per 67 milliliters of urine.

DUI urine tests may be more accurate than breathalyzers, but that doesn’t mean the process is without issues. Urine samples can be easily contaminated or diluted if they aren’t transported and stored correctly. Not only this, but urine tests calculate data for all substances in your system at that moment. That means if you have terpenes from a controlled substance in your system, it will show up on a drug test. The problem with this is some drugs will remain in your system for days, weeks, and in some cases months.

That means the test may pick up on substances you used days, weeks, or months ago. Law enforcement might take this information and then infer you were high at the time of the traffic stop. This has caused many innocent people to be accused of DWI.

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What Happens If You Refuse to Take a BAC Test in Texas?

While you can refuse BAC tests such as urine analysis, it’s important to understand you’ll be in violation of implied consent laws. These are a set of laws that state you’re implicitly agreeing to chemical testing by law enforcement if you’re driving on a public Texas road or highway. Only chemical tests involving breath, blood, or urine samples are included in implied consent laws. Field sobriety tests can be refused and doing so will not violate implied consent laws.

Refusing implied consent laws will result in an administrative penalty. You won’t face time in jail or any exorbitant fines, but your license will be suspended. The following are the suspension terms for refusing to submit to BAC testing by law enforcement.

While it’s a burden to not have a car in the state of Texas, it may be the best decision to refuse urine analysis when asked. If you refuse BAC testing, the prosecution will have little to no scientific evidence of your intoxication. It will be difficult for them to take the case to trial as they will only have objective evidence from the officer’s testimony and body-cam footage. That means prosecutors are much more likely to allow you to plead out or even dismiss your charges if you refuse chemical testing from law enforcement.

However, it’s important to know a refusal can result in your eventual arrest. Refusing testing is often seen as evidence of guilt from police officers, so they may arrest you because of it. What’s important to remember is that if you submitted and failed testing, you would be arrested anyway. So, refusing may seem scary with a possible arrest looming, but if you submit and fail now the prosecution has evidence of your intoxication AND you’ll still go to jail.

If you submit to urine resting and fail, then you license could be suspended up to:

  • 90 days for your first offense; and
  • 1 year for your second or subsequent offense

Refusing is usually the best course of action if you are intoxicated and an officer pulls you over. While you might be arrested, it’s better to not give the prosecution ammo for their case. Plus, once you’re bailed out you can contest your license suspension immediately. You only have 15 days to file a request for an Administrative License Revocation hearing, and at that hearing you can argue why the suspension isn’t necessary.

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What Can Affect Urinalysis Results for DUI?

Urine testing, while more accurate than breathalyzers, isn’t the most dependable method to measure a person’s blood-alcohol concentration. The samples are very delicate and must be transported and stored in a specific way. Failure to do so can result in a contaminated or diluted sample. In addition to this, urine analysis detects terpenes of all substances in your system. The issue with that is some substances terpenes will remain in your system for days, weeks, or even months.

So, it’s very possible you could be accused of driving while under the influence of drugs because of your urinalysis results. Despite the fact that you used the substance days, weeks, or even months before the traffic stop. Listed below are some detection times for common controlled substances that may show up in a urine test.


Type of Drug: Detection Time
Lysergic Acid Diethylamide (LSD) One day
Cocaine One day
Ketamine Two days
MDMA, Ecstasy, or Molly Two days
Amphetamine Three Days
Codeine Three Days
Fentanyl Three Days
Hydrocodone Three Days
Oxycodone Three Days
Methamphetamine Three Days
Morphine Three Days
Moderate Marijuana Use Five Days
Flunitrazepam Five Days
Methadone Seven Days
Phencyclidine (PCP Eight days
Marijuana Daily Use 10 days
Diazepam 10 days
Marijuana Chronic Use 30 days

Other factors that could result in skewed or false urinalysis results includes:

  • Sample tampering
  • Using expired testing kits
  • Faulty testing kits
  • Problems with sample seals
  • Incorrectly interpreted results
  • Improper storing
  • Diluted samples

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Additional Resources

Texas DWI Laws – Visit the official website of Texas Penal Code to learn more about driving while intoxicated (DWI) and other related offenses. Access the site to learn more about DWI charge specifics, penalties, aggravating factors, and other important information.

Administrative License Revocation Program – Visit the official website of the Texas Department of Public Safety (DPS) to learn more about administrative penalties for refusing chemical testing. Learn the suspension terms for minors, non-commercial adult drivers, and commercial drivers (CDL holders). You can also find a link to file a request for an administrative license revocation hearing.

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DUI Urine Test Attorney in Harris County, Texas

If you or someone you know has been charged with DWI for submitting or refusing a BAC test, we urge you to call Horak Law. Matthew Horak has been practicing law since 2003 and can utilize his extensive trial experience to help you and your case. He can assess your charges, explain your legal options, and begin building your defense right then and there.

Call Horak Law today at (713) 225-8000 to set up your first consultation free of charge. Horak Law accepts clients throughout the greater Houston and The Woodlands greater area including Humble, Pasadena, Cypress, South Houston, Bellaire, Montgomery, Conroe, Willis, Splendora, Magnolia, Hempstead, Liberty, Dayton, Hardin, Sugar Land, Richmond, Rosenberg, Fresno, Brazoria, Lake Jackson, Alvin, Freeport, Manvel, Galveston, Kemah, Dickinson, La Marque, and Santa Fe.

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  • Texas Board of Legal Specialization | Criminal Law
  • National College for DUI Defense
  • National Association of Criminal Defense Laywers
  • Harris County Criminal Lawyers Association
  • Matt Horak has earned recognition for community leadership by Lawyer Legion